Although the doctrine bears the name of President James Monroe, he was not the doctrine's principal author. It is widely accepted that John Quincy Adams's greatest diplomatic service was in his role as secretary of state during James Monroe's two terms as president. It was Adams who, as secretary of state, suggested and outlined the Monroe Doctrine, which gave an important grounding for the future development of the country on the world stage.

Adams also was a talented negotiator. He helped to negotiate the Treaty of Ghent and put an end to the War of 1812 by it. He is widely considered to be one of the most prominent and gifted diplomats and secretaries of state in the history of the US.

More Info: en.wikipedia.org